Re: Spanning Tree Question - Root Port Selection
Nathan, Check the original paper by Radia Perlman, or better yet have a read of Chapter 3 of her book "Interconnections - Bridges, Routers, switches and Internetworking Protocols" 2nd Edition. Serge :) - Original Message - From: "Miller, Nathan - BSC" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, February 06, 2001 2:08 PM Subject: Spanning Tree Question - Root Port Selection I have been looking for a while for further documentation of the process by which a switch selects its root port. Most of the books that I have searched for this information say something similar to the following quote from a CCO page: "A bridge's root port is the port through which the root bridge can be reached with the least aggregate path cost, a value that is called the root path cost." My problem is that they all seem to stop there. My question is this. If the root path cost is the same on multiple switch ports, how does STA determine which is the root port? Does it follow the same course as it would when selecting a designated port (root bridge, root path cost, sender ID, sender port). Many thanks for your thoughts. Nathan Miller _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Patch Panel and Cisco 2511
Tai, You need to be careful with the run length, but I have a feeling that the problem is more to do with your pin-outs Check out: http://www.cisco.com/univercd/cc/td/doc/product/access/acs_fix/cis2500/2509/ acsvrug/cables.htm#xtocid402311 (watch out for the wrap!) Alternatives are using the Aux port, or get one of those 2511, and use reverse telnet! Serge :) - Original Message - From: Tai Ngo [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, November 21, 2000 6:58 PM Subject: Patch Panel and Cisco 2511 Hi All, I have setup console access to my routers via the Cisco RJ-2511 router. Everything works fine if all my routers are in the same room as my console server. However, I am having problems getting it to work across patch panels. I connect the roll cable from my router console port to the patch panel which connects to a patch panel in my server room. I then connect another roll cable from the server room's patch panel to the console server. When I try to telnet into the port, it just sits there. I have tested all the roll cables and the patch panel ports to make sure they work. Have I left something out? _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ISDN PRI MODULE
Hi Willy! Balanced and Unbalanced is a term carried over from transmission line theory...ie., any form of energy transfer between two points. (It overs data, microwave, telephone circuits, radio antenna, as well as high-voltage power distribution!) A balanced line uses two channels (ie., conductors) for energy transmission. What happens is that the voltage of the two conductors are equal in strength, but opposite in direction (ie., positive and negative voltages) with respect to ground, in this way any induced voltages (ie., interference) are minimised = you can run this type of cable over longer distances without corrupting the original voltage (ie., data). Example: G.703 interface, twin-ax cable, Cat-5 cable, RS-442, POTS copper line (ie., TIP and RING) etc., Advantage: Longer distance runs with less corruption on the channel Disadvantage: More complicated end interfaces and tends to require closer tolerances for the cable = more expensive! An un-balanced line is one in which the voltages are not equal, with respect to ground. Example: X.21 interface, RS-232, TV/Radio coax cable etc., Advantage: Cheaper cable, line drivers (ie., interfaces) are cheaper as well Disadvantage: Not suitable for long distance runs I hope that helps...on the balanced and un'balanced front! Regards, Serge :) - Original Message - From: willy george [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, November 19, 2000 2:35 PM Subject: ISDN PRI MODULE Dear All, I have noticed that when you order an ISDN PRI module for a modular router there are two choices available. Balanced and Unbalanced. Could any one please tell me what the difference is between the two and what is the advantage of using either one of them?. I have also noticed a line "Processmaxtime=200" in the configs of some routers. What exactly does this particular line signify? Thanks in advance for your time Willy _ Chat with your friends as soon as they come online. Get Rediff Bol at http://bol.rediff.com Participate in crazy auctions at http://auctions.rediff.com/auctions/ _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: what is the purpose of FECN?
FECN - Forward Explicit Congestion Notification This is a bit within the address field which notifies the receiving device that the network is experiencing congestion. The end device (ie., router, FRAD etc.) is informed that congestion was experienced on route...subsequent packets could be delayed, discarded or even damaged. The end device *should* take remedial action to adjust to the new transmission environment, from the source...ie., inform the source to "throttle-back". This is achieved by using a complimentary bit field in the address field...BECN (Backward Explicit Congestion Notification)...in packets sent to the source router/FRAD. In the real world, what tends to happen, is that there is no way traffic from upstream hosts (ie., PC's, servers etc.) can be slowed down to the router/FRAD. Increasing the size of the buffers (ie., memory) at the source router helps, but this is useless in the face of severe packet loss to the destination. Hence, the concept of "Becky and Fecky" can only be really used to detect congestion, by setting SNMP trap conditions, not give *real* throttle-control, as the text books would describe! Without a though the answers: A Regards, Serge :) - Original Message - From: Shaw, Winston Mr. [EMAIL PROTECTED] To: 'cslx' [EMAIL PROTECTED]; [EMAIL PROTECTED] Sent: Sunday, November 19, 2000 6:25 PM Subject: RE: what is the purpose of FECN? Looks like a trick question. I would choose answer a. Answer b corresponds to what is called the BECN. The reason that it is a trick question is that the immediate reaction would be to discard Answer a because FECN is not the only way to tell if a packet experienced congestion. Winston. -Original Message- From: cslx [mailto:[EMAIL PROTECTED]] Sent: Sunday, November 19, 2000 10:39 AM To: [EMAIL PROTECTED] Subject: what is the purpose of FECN? what is the purpose of FECN? a.To tell the router that a packet experienced congestion b.To tell the router that packets it is sending to a remote site are experiencing congestion c.To tell the router that there is bandwidth available _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: free Cisco VPN Book
I've been "ordering" free books from the cisco web site for serveral years now, as well as from other vendors sites. Let me see...that's a total of 6 books complimentary of Cisco, and another 3 from Nortel, and still counting! Oh yes, nearly forgot about the free t-shirts, and other freebies I've been sent. I must have been sent well over US$200 worth of items, including shipping! There are offers all the time, just keep on filling in the form as usual...I've *always* got the item in the end...sometimes it's taken over 2 months! Another thing, Cisco is located in practically every country in the world...! Serge :) Ps. I live in the UK! - Original Message - From: Rann Sanders [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, September 12, 2000 10:18 PM Subject: Fw: free Cisco VPN Book Wow! No way! Really? :-) Rann Sanders, MCPx3 Network Engineer DaVita - Original Message - From: "John Kaberna" [EMAIL PROTECTED] To: "Rann Sanders" [EMAIL PROTECTED]; "Hubert Pun" [EMAIL PROTECTED]; "Kenneth Lorenzo" [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Tuesday, September 12, 2000 1:53 PM Subject: Re: free Cisco VPN Book ARE YOU PEOPLE STUPID?? They don't want to send stuff to other countries likely because of the high cost of shipping overseas. Dammit people get a grip. Cisco is based in the US and I doubt they are going to stock these books all over the world. Amazing how clueless some of you people are. John - Original Message - From: Rann Sanders [EMAIL PROTECTED] To: Hubert Pun [EMAIL PROTECTED]; Kenneth Lorenzo [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Tuesday, September 12, 2000 1:28 PM Subject: Re: free Cisco VPN Book If I remember correctly, there's been discussion on here, in the past, regarding Cisco's dislike for sending "free offers" to other countries. I imagine the lack of these countries being listed is not accidental. Rann Sanders, MCPx3 Network Engineer DaVita - Original Message - From: "Hubert Pun" [EMAIL PROTECTED] To: "Kenneth Lorenzo" [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Monday, September 11, 2000 3:03 PM Subject: Re: free Cisco VPN Book Where is Canada in the "country" option? **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Total Renal Care **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] Total Renal Care **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
